The present invention relates to tools, including clamping, holding and gripping type tools. More specifically, the present invention relates to clamping, holding and gripping type tools, including such tools adapted to apply a treatment to a workpiece. In some embodiments, the treatment may be selected as suitable for the workpiece to be held, clamped or gripped and for the effect sought.
Various circumstances require a clamping tool. Repair, joining or sealing conduits, pipes and the like or other workpieces may be facilitated by clamping. Often, it is advantageous to pinch or otherwise block piping through which fluid is moving. For example, a utility crew may expose a portion of a natural gas line to perform maintenance or some other type of work. The utility crew cannot access the pipe without controlling the flow of the fluid, yet it may be difficult and disruptive to cease flow to that entire line. Thus, a clamp is often used to pinch the pipe or otherwise block the piping to stop fluid flow from that point forward.
Alternatively, a clamping tool may be used to clamp a pipe or conduit and apply a treatment thereto, without disturbing the flow of the fluid through the pipe or conduit.
A number of tools have been created to address these tasks. Some of the difficulties common to these tools include positioning of the tool around the pipe within a confined area, clamping the pipe without expelling it from the tool, providing a configuration offering sufficient force to compress the pipe, and providing a treatment to the pipe. These difficulties act individually and collectively to make it more difficult to use a clamping tool to secure a pipe or conduit and stop fluid flow through the pipe or conduit.
Generally, when securing a pipe to stop fluid flow through the pipe, only a small area is provided to work in. For example, a trench may be dug through the ground to reveal a small segment of the pipe. This can make it difficult to access the pipe, to reach the pipe (it may be several feet below ground level), and to engage the pipe with a tool. Because of the generally cylindrical shape of pipes, the strength of pipes, and the typical “scissoring” (i.e., angled closing) effect of clamping tools, pipes often become expelled from the clamping tool as the tool is actuated. That is, the pipe may not be easy to compress and, as the tool closes, the angled closing may cause the tool to disengage rather than clamping the pipe.
The small workspace, the resistance of the pipe to clamping, and the depth of the pipe in the ground make it difficult to provide a tool that an operator can use to develop sufficient force to apply a treatment to a pipe or to stop fluid flow through the pipe. Traditionally, when manually operated tools are needed to exert a greater force, a longer lever arm is provided. However, such a solution, in this context, is impractical for the reasons previously noted.
In some applications, it would be helpful if a radially directed force could be applied substantially completely and uniformly around a workpiece using a clamping or gripping type tool. This is difficult with a traditional scissor type jaw movement, or with clamp type tools having the typical generally flat jaw surfaces.
Thus, there exists a need to provide an improved clamping tool.